In a large skillet, heat the vegetable oil over medium-high heat.
Add the beef tips in batches and brown on all sides, about 3-4 minutes per batch. Transfer browned beef tips to a slow cooker or large pot.
In the same skillet, add the chopped onion and cook until softened, about 5 minutes.
Add the minced garlic and cook for 1 minute more.
Pour in the beef broth and water, scraping up any browned bits from the bottom of the skillet.
Stir in Worcestershire sauce, dried thyme, salt, black pepper, and paprika.
Pour the mixture over the beef tips in the slow cooker or pot.
Cover and cook on low heat for 1 hour 30 minutes, or until beef tips are tender.
In a small bowl, whisk together the all-purpose flour and cold water until smooth to make a slurry.
Stir the slurry into the beef and gravy mixture and cook for an additional 5-10 minutes, stirring frequently, until the gravy thickens.
Allow the beef tips and gravy to cool completely before transferring to freezer-safe containers.
Label and freeze for up to 3 months.
To reheat, thaw overnight in the refrigerator and warm gently on the stovetop or in the microwave until heated through.